This implements remaining part of P2679R2, "Fixing std::start_lifetime_as
and std::start_lifetime_as_array".
For incomplete type _Tp, the is_implicit_lifetime_v<_Tp> check inside
start_lifetime_as already leads to following "invalid use of incomplete
type 'struct Incomplete'" error.
libstdc++-v3/ChangeLog:
* include/bits/stl_construct.h (std::start_lifetime_as_array):
static_assert that _Tp is complete type.
* testsuite/std/memory/start_lifetime_as/neg.cc: New test.
---
Testing on x86_64-linux. *start_lifetime* test already passed.
OK for trunk when all tests passes?
libstdc++-v3/include/bits/stl_construct.h | 8 ++++
.../std/memory/start_lifetime_as/neg.cc | 45 +++++++++++++++++++
2 files changed, 53 insertions(+)
create mode 100644 libstdc++-v3/testsuite/std/memory/start_lifetime_as/neg.cc
diff --git a/libstdc++-v3/include/bits/stl_construct.h
b/libstdc++-v3/include/bits/stl_construct.h
index 4a0650f3cb8..9608d7fd8ca 100644
--- a/libstdc++-v3/include/bits/stl_construct.h
+++ b/libstdc++-v3/include/bits/stl_construct.h
@@ -346,6 +346,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _Tp*
start_lifetime_as_array(void* __p, size_t __n) noexcept
{
+ static_assert(sizeof(_Tp), "template argument must be a complete type");
+
auto __q = reinterpret_cast<_Tp*>(__p);
if (!__n)
return __q;
@@ -360,6 +362,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline const _Tp*
start_lifetime_as_array(const void* __p, size_t __n) noexcept
{
+ static_assert(sizeof(_Tp), "template argument must be a complete type");
+
auto __q = reinterpret_cast<const _Tp*>(__p);
if (!__n)
return __q;
@@ -376,6 +380,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline volatile _Tp*
start_lifetime_as_array(volatile void* __p, size_t __n) noexcept
{
+ static_assert(sizeof(_Tp), "template argument must be a complete type");
+
auto __q = reinterpret_cast<volatile _Tp*>(__p);
if (!__n)
return __q;
@@ -392,6 +398,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline const volatile _Tp*
start_lifetime_as_array(const volatile void* __p, size_t __n) noexcept
{
+ static_assert(sizeof(_Tp), "template argument must be a complete type");
+
auto __q = reinterpret_cast<const volatile _Tp*>(__p);
if (!__n)
return __q;
diff --git a/libstdc++-v3/testsuite/std/memory/start_lifetime_as/neg.cc
b/libstdc++-v3/testsuite/std/memory/start_lifetime_as/neg.cc
new file mode 100644
index 00000000000..1adbd2f266d
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/memory/start_lifetime_as/neg.cc
@@ -0,0 +1,45 @@
+// { dg-do compile { target c++23 } }
+
+#include <bit>
+#include <memory>
+
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+struct Incomplete;
+struct NonTrivial
+{
+ NonTrivial() {}
+ ~NonTrivial() {}
+};
+
+void test(void* p)
+{
+ (void)std::start_lifetime_as<Incomplete>(p); // { dg-error "here" }
+ (void)std::start_lifetime_as_array<Incomplete>(p, 2); // { dg-error "here"
}
+ (void)std::start_lifetime_as<NonTrivial>(p); // { dg-error "here" }
+ // Array are implicit-lifetime regardless of they element type
+ (void)std::start_lifetime_as_array<NonTrivial>(p, 2);
+
+ const void* cp = p;
+ (void)std::start_lifetime_as<Incomplete>(cp); // { dg-error "here"
}
+ (void)std::start_lifetime_as_array<Incomplete>(cp, 2); // { dg-error "here"
}
+ (void)std::start_lifetime_as<NonTrivial>(cp); // { dg-error "here"
}
+ (void)std::start_lifetime_as_array<NonTrivial>(cp, 2);
+
+ volatile void* vp = p;
+ (void)std::start_lifetime_as<Incomplete>(vp); // { dg-error "here"
}
+ (void)std::start_lifetime_as_array<Incomplete>(vp, 2); // { dg-error "here"
}
+ (void)std::start_lifetime_as<NonTrivial>(vp); // { dg-error "here"
}
+ (void)std::start_lifetime_as_array<NonTrivial>(vp, 2);
+
+ const volatile void* cvp = vp;
+ (void)std::start_lifetime_as<Incomplete>(cvp); // { dg-error
"here" }
+ (void)std::start_lifetime_as_array<Incomplete>(cvp, 2); // { dg-error
"here" }
+ (void)std::start_lifetime_as<NonTrivial>(cvp); // { dg-error
"here" }
+ (void)std::start_lifetime_as_array<NonTrivial>(cvp, 2);
+}
+
+// { dg-prune-output "invalid use of incomplete type" }
+// { dg-prune-output "template argument must be a complete type" }
+// { dg-prune-output "static assertion" }
--
2.54.0
